Characterization of human papillomavirus genotypes and their coverage in vaccine delivered to Ethiopian women

Cervical cancer is a significant public health concern in Ethiopia. It is mainly caused by persistent infection with the human papillomaviruses. The aim of this study was to assess the relationship between carcinogenic risk of probable, possible and low risk HPV infection and those of cervical intraepithelial neoplasia (CIN) and cervical cancer. A cross sectional study nested from prospective cohort study was conducted in Bahir Dar, northwest Ethiopia. Statistical analyses were performed using SPSSversion 26.0. HPV-16 was associated with a relatively higher risk of CIN II+, (AOR = 15.42; 95% CI 6.81–34.91). In addition, HPV-52, -18, -53 and -58, were significantly associated with an increased risk of CIN II+, (AOR = 7.38 (1.73–31.54), 5.42 (1.61–18.31), 4.08 (1.53–10.87), and 3.17 (1.00–10.03)), respectively. The current study shows high rate of HPV with predominance of HPV-16, -53, -58, -18, -35, and -52. The quadrivalent and nonavalent vaccine had only covered 27.1% and 45% of the circulating HPV genotypes. Ethiopia may need to consider introduction of nonavalent vaccine into the national public health strategy. Polyvalent vaccine which includes the genotypes not covered by existing approved vaccines should be considered.

as the main risk factor.The impact of specific HPV types on cervical cancer incidence can differ across locations, likely attributable to geographic variations in the prevalence of HPV types within different populations.The likelihood of progression from HPV infection to cervical cancer can also vary depending on the HPV genotype 6 .
Cervical cancer is the second most common cancer, next to breast cancer among women worldwide.Despite being one of the most preventable tumors among all major human cancers, the frequency of new cases of cervical cancer is rising steadily 7 .
Cervical cancer is a significant public health concern in Ethiopia, particularly among women between the ages of 15 and 44 8 .It is the most frequent malignancy affecting this population.Recent estimates indicate that approximately 7445 new cases of cervical cancer are diagnosed annually in the country, leading to the loss of 5338 women's lives each year 9 .
Epidemiological studies are crucial for screening and immunization programs in addition to providing a thorough understanding and assessment of the risk of Cervical Cancer (CC) development in women infected with HR-HPV types 10 .The 2-valent HPV vaccine (Cervarix, 2vHPV), 4-valent HPV vaccine (Gardasil, 4vHPV), and 9-valent HPV vaccine (Gardasil 9, 9vHPV) are the three licensed HPV vaccinations that are currently available to prevent cervical cancer 11 .HPV-16 and -18, the two main kinds of HPV that cause cancer, HPV-6 and HPV-11, are protected against by the 2-and 4-valent vaccines; additionally, the 9-valent vaccine offers protection against HPV-31, -33, -45, -52, and -58 6 .
Since the current vaccines, particularly a quadrivalent vaccine given in Ethiopia, only provide a limited amount of cross-protection, gathering scientific data on the prevalence of HPV, genotype distribution, cytological profile, and related factors across various populations is crucial to forecasting the vaccine's effectiveness and developing new vaccination strategies 12 .
In this study, we assessed the association between carcinogenic risk of probable, possible and low risk HPV infection and those of cervical intraepithelial neoplasia (CIN) and cervical carcinoma.

Results
A total of 297 women attending gynecology unit of Felege Hiwot Comprehensive Specialized Hospital were participated in the study.About 61.3% (182/297) of the participants live in rural area, majority of study participants (84.5%) were illiterates, more than half of study participants (63%) were married (Table 1).

Discussion
The results of this study revealed that 139 (46.8%) of the study participants had an overall prevalence of HPV.This finding was in line with the results of another Ethiopian study that found 53.0% of women with cervical abnormalities being infected with HPV 13 .This finding is also consistent with research conducted in South Africa, where the total prevalence of HR-HPV DNA was 48.1% 14 , and Europe, where the study population's overall HPV prevalence was reported to be 50.8% 15.
Our finding indicated overall, there were 56 (18.85%) study participants with CIN II + (classified as diseased) with pathology examination.Of CIN II + , 54/56 (96.43%) had HPV infection whereas two out of fifty six (3.57%) did not have HPV infection.The prevalence of HPV among women with CIN II + was higher compared to women with CIN II − .This finding is similar with another study conducted in South Africa which detected HPV infection in 84.2% (383/455) of women 16 .
This result is also in line with a Chinese study that found women with abnormal cervical lesions and cervical cancer as having high HPV prevalence compared to women with normal cervical histology 10.5% for the Negative for Intraepithelial Lesion or Malignancy (NILM), 73.9% for CIN1, 89.5% for CIN2, and 91.5% for ≥ CIN3 17 .The study conducted in India also reported the prevalence of high risk HPV infection to be 93.3% in participants with invasive cervical cancer and 46.1% in those with precancerous lesions, indicating that HPV is a significant risk factor for cervical cancer 18 .
The distribution of HPV genotypes is different in different parts of the world and among different studies [22][23][24][25][26][27][28] .The heterogeneity observed in the HPV genotype distribution among the studies could be attributed to variations in the spread of the HPV virus, sociodemographic composition of the study population, the degree of cervical lesions, and the diagnostic techniques used when examining women with abnormalities.
The most significant approach both to prevent and eradicate cervical cancer is vaccination.The U.S. Food and Drug Administration (FDA) has approved three HPV vaccines: the bivalent HPV vaccine (Cervarix, 2vHPV), the quadrivalent HPV vaccine (Gardasil, 4vHPV), and the nonavalent HPV vaccine (Gardasil 9, 9vHPV).Ethiopia launched the quadrivalent vaccination for the first time in December 2018 targeting 14-year-old girls, with the support of the Global Alliance for Vaccine and Immunization (GAVI) 30 .The results of our study showed that 25% of the genotypes were covered by the bivalent vaccine (HPV-16/18).The quadrivalent (HPV-6, -11, -16, and -18) vaccination had a coverage rate of 27.1% and the nonavalent vaccine had a coverage rate of 45%.In line with our findings, a systematic review conducted among women in West Africa, found that 15.1% of the genotypes identified were covered by the bivalent vaccine (HPV-16/18).Furthermore, the nonavalent vaccine's additional high-risk carcinogenic HPVs (HPV-31/33/45/52/58) showed a prevalence of 37.6%.Thus, the nonavalent vaccine had a coverage rate of 55.8%.The prevalence of the HPV-35/39/51/56/59/66/68 genotypes, which are not protected by a vaccine, was 44.2% 30 .
In our study, the proportion of HPV genotypes non-covered by the existing vaccine was 132/240 (55%).This finding was consistent with a study conducted in Ethiopia that reported the prevalence of non-vaccine-targeted HPV was 56 (51.8%, 95% CI 0.42, 0.61) 31 .

Conclusion
The prevalence of HPV among Ethiopian women was found to be high with predominance of HPV-16, -53, -58, -18, -35 and, -52.HPV-16, HPV-52, HPV-18, HPV-53, and HPV-58 were associated with the highest risk of CIN II + .In our study the quadrivalent and nonavalent vaccine had 27.1% and 45% coverage.Ethiopia may need to consider introduction of nonavalent vaccine into the national public health strategy as part of a comprehensive approach to cervical cancer prevention and control.Polyvalent vaccine which includes the genotypes not covered by existing vaccines should be considered to prevent the spread of HPV and cervical cancer.

Study setting and population
A cross sectional study nested from prospective cohort study was conducted between January and December 2023 among patients attending the gynecology unit of Felege Hiwot Comprehensive Specialized Hospital (FHCSH) in Bahir Dar, northwestern Ethiopia.A total of 324 women of age above 30 and HIV positive women with all age range (according to WHO recommendation for screening) who visited FHCSH Gynecological unit who come for gynecological complaints such as vaginal bleeding, vaginal discharge, abdominal pain, back pain, Difficulty of urination, difficulty of defecation, protruded mass per vagina, burning sensation and itching, pain during sexual intercourse and urination during data collection time were enrolled, but 27 of them had insufficient PAP smears and they were excluded from the study, the rest 297 were included and all gave their informed consent to participate in the study.All women who visit FHCSH gynecological unit, above 30 years old and willing to participate in the study were included.Although the age of HIV positive women was less than 30, they were included in the study.All women who took any kind of treatment for cervical cancer or any vaginal medication, vaginal contraceptives or douches 48 h prior to the test, those who had sexual intercourse 24 h before the test; women who are in menstruation, pregnant and women who had hysterectomy were excluded from the study.
All of the study participants were screened with Visual acetic acid test (VIA), genotyping of the HPV DNA test and cervical cytology examination with the PAP test.Study participants with positive results from screening tests were examined with colposcopy and biopsy was taken for histopathology.

Source population
The study population was all women of age above 30 and HIV positive women with all age range who visited FHCSH Gynecological unit during data collection time.

Study population
The study population was all women of age above 30 and HIV positive women with all age range who visited FHCSH Gynecological unit and suspected for cervical cancer.

Sample size determination
Study one: A single population proportion sample size determination formula (study population size less than 10,000 32 ) was used with the assumption of 19% proportion of HPV, 5% margin of error, and 95% desired level of confidence interval and considering a 10% non-response rate, the sample size was 281.
Study two: Sample size was determined from formulation of sensitivity and specificity test using Power Analysis and Sample Size (PASS) software based on desired type I error, power and effect size 33 .The minimum sample size was determined by taking the prevalence of a disease 19%, by assuming sensitivity of the kit is comparable with the gold standard, and specificity of the kit is greater than 70%, the power is set to be at least 80% and the P-value, is set to be less than 0.05.The sample size for sensitivity and specificity of Onco E6 performance study was 49 positive for histopathology, 196 negative samples with the gold standard histopathology examination and 49 negative controls.By taking 10% contingency, the sample size was 324.The final sample size was the highest sample size of the upper studies, 324 sample size was determined for this study.

Table 2 .
Characteristics of the study population among women attended cervical unit of FHCSH from January and December 2023.

Table 3 .
Individual occurrence of HPV according to histological examination among women attended cervical unit of FHCSH from January and December 2023.*16 of Type 53 occur with Probable HPV, **8 of Type 70 occur with probable HPV.

Table 4 .
Bivariate logistic regression analysis of HPV genotypes according to histological examination among among women attended cervical unit of FHCSH from January and December 2023.

Table 5 .
Multivariate logistic regression analysis of HPV genotypes according to histological examination among women attended cervical unit of FHCSH from January and December 2023.

Table 6 .
Coverage rate of HPV genotypes by HPV vaccine among women attended cervical unit of FHCSH from January and December 2023.